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Table 2 Median (range) of differences between the cumulated dose considering the anatomy in the control CTs, D cCT , and the nominal plan dose D pCT . A positive number indicates a higher value of D cCT . Significant differences (paired t-test, p < 0.05) are marked by*

From: Impact of robust treatment planning on single- and multi-field optimized plans for proton beam therapy of unilateral head and neck target volumes

ROI Parameter MFOPTV MFORob SFOPTV SFORob
Low-risk CTV
ΔD98% / pp −0.09 0.16 0 0.05
  (−3.62–0.58) (−0.58–0.58) (−4.14–0.76) (−2.70–0.32)
High-risk CTV
ΔD98% / pp 0.15 −0.53 −0.18 −0.78*
  (−1.03–1.94) (−3.41–0.16) (−2.50–0.16) (−2.65 − −0.21)
ΔD2% / pp 0.18 −0.31* −0.46* −0.63*
  (−0.29–5.51) (−0.88 − −0.06) (−0.91 − −0.13) (−0.94 − −0.34)
Spinal Cord
ΔD1cc / Gy 0.57 0.61 0.46 0.59*
  (−1.21–1.15) (−0.82–1.04) (−0.72–0.99) (−0.80–1.22)
Brainstem
ΔD1cc / Gy 0.61 0.13 0.15 0.17
  (−0.82–1.04) (−0.14–1.80) (−0.24–1.14) (−0.17–1.39)
Parotid Ipsilateral
ΔDmedian / Gy 0.66 0.04 −0.31 −0.34
  (−0.02–2.39) (−1.66–1.78) (−2.02–1.34) (−2.66–1.34)
Larynx
ΔDmean / Gy 1.21 0.89 1.21 0.9
  (−1.37–8.58) (−1.28–6.60) (−1.51–8.86) (−1.29–6.97)
Oral Mucosa
ΔDmean / Gy −0.05 0.02 0.01 0.06
  (−0.48–1.79) (−0.20–1.61) (−0.72–1.72) (−0.71–1.54)
Constrictor Muscles
ΔDmean / Gy 0.1 −0.11 0.05 0.05
  (−2.05–2.83) (−2.09–2.35) (−2.45–4.16) (−2.24–2.91)
Esophageal inlet
ΔDmean / Gy 0.57 0.44 0.57 0.5
  (−1.67–7.84) (−1.20–5.23) (−1.64–8.15) (−1.28–5.53)
  1. Abbreviations: pp. Percentage points, D 98% Minimum dose to the 98% of the target volume, D 2% Minimum dose to the 2% of the target volume, D mean Mean dose, D median Median dose